(a) Field of the Invention
The present invention relates to a transmitter of a communication system and a method for configuring a pilot channel. More particularly, the present invention relates to a method for configuring a pilot channel in a frequency division multiple access (FDMA) communication system.
(b) Description of the Related Art
Frequency division multiple access (FDMA) channels for individual users include a localized FDMA (L-FDMA) channel and a distributed FDMA (D-FDMA) channel. In an L-FDMA method, symbols are allocated to contiguous subcarriers, which is efficient for allocating a local frequency having excellent characteristics for each user. In a D-FDMA method for allocating a distributed frequency to guarantee frequency diversity, symbols are allocated to equi-spaced subcarriers.
A transmitting terminal transmits a pilot signal to a receiving terminal so that the receiving terminal may estimate a value of a channel path. Since subcarriers forming the L-FDMA channel are contiguous in frequency domain, pilot information on only some subcarriers suffice to estimate channel response of a whole subcarriers belong to an interesting L-FDMA channel at receiver side. Accordingly, a length of a pilot block may be reduced to less than a length of a data block. However, since the D-FDMA channel consists of equi-spaced subcarriers, it is difficult to reduce the length of the pilot block to be shorter than that of the data block.
Accordingly, it is required to form a pilot block to be applied to the above two kinds of channel types so as to simultaneously support the L-FDMA channel and the D-FDMA channel in the communication system, and it is required to maintain a ratio of entire data to pilot to be lower than a predetermined ratio so as to efficiently perform communication.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.